a. Field of the Invention
This invention relates generally to medical instruments, and, more specifically, to a guide and flexible sleeve for use with catheters for ablation or other medical procedures.
b. Background Art
Catheters are flexible, tubular devices that are widely used by physicians performing medical procedures to gain access into interior regions of the body. Careful and precise positioning of the catheters within the body is important to successfully completing such medical procedures. It is well known that benefits can be and/or are gained by using catheters to form lesions in tissue if the depth and location of the lesions being formed can be controlled. For example, it can be desirable to elevate tissue temperature to around 50° C. until lesions are formed via coagulation necrosis, which changes the electrical properties of the tissue. Lesions can be and/or are formed at specific locations in cardiac tissue via coagulation necrosis to lessen or eliminate undesirable atrial fibrillation.
Several difficulties can be and/or are encountered, however, when attempting to form lesions at specific locations using some existing ablation electrodes. One such difficulty encountered with existing ablation catheters is how to locate the tissue and maintain catheter contact with the tissue at the desired location during the procedure. These assessments are not readily determined using conventional fluoroscopy techniques. Instead, the physician locates and maintains contact between the catheter and the tissue based on his/her experience using the catheter. Such experience only comes with time, and can be and/or are quickly lost if the physician does not use the catheter on a regular basis. In addition, when forming lesions in a heart, the beating of the heart further complicates matters, making it difficult to maintain sufficient contact pressure in a fixed location between the catheter and the tissue for a sufficient length of time to form a desired lesion. If the contact between the catheter and the tissue cannot be properly maintained, a quality lesion is unlikely to be created.